Hi, the vertex form of a Parabola opening up(a>0) or down(a<0), where(h,k) is the vertex and x = h is the Line of Symmetry Parabola opening Downward a = -1 < 0 y= -x^2+1 V(0,1) x = 0 the line of symmetry & When y = 0, x = ± 1
